Copper nickel alloys

ABSTRACT

A high quality, high strength, highly ductile, castable, weldable and corrosion resistant Copper alloy consisting of the following elements in the following proportions by weight : Nickel 9% - 18% Aluminium 1% - 3.5% Manganese 8.5% - 13% Iron 2.5% - 6.5% Chromium 0% - 1% Copper the balance WITH THE Aluminium, Manganese and Nickel contents being so controlled t

Ute States Patent 1 ichardson et al.

[ 51 Oct. 30,1973

[54E COPPER NICKEL ALLOYS [731 Assignee: Langley Alloys Limited, Slough,

Buckinghamshire, England [22] Filed: July 7, 1971 [21] Appl. No.: 160,531

Related U.S. Application Data {63] Continuation-in-part of Ser. No. 784,024, Dec. 12,

1968, abandoned.

[52] U.S. Cl 75/159, 148/32, 148/32.5 [51] Int. Cl. C22c 9/06 [58] Field of Search 75/153, 159, 161,

[56] References Cited UNITED STATES PATENTS 3,399,057 8/1968 Richardson 75/159 FOREIGN PATENTS OR APPLICATIONS 578,223 6/1946 Great Britain 75/159 655,931 Germany 75/159 l/1938 1,194,632 6/1970 Great Britain 75/159 1,090,734 11/1967 Great Britain..... 75/159 999,438 7/1965 Great Britain 75/159 Primary Examiner-Charles N. Lovell Attorney-Luke A. Mattare et al.

[57] ABSTRACT A high quality, high strength, highly ductile, castable, weldable and corrosion resistant Copper alloy consisting of the following elements in the following proportions by weight Nickel 9% 18% Aluminium 1% 3.5%

Manganese 8.5% 13% Iron 2.5% 6.5%

Chromium 0% 1% Copper the balance with the Aluminium, Manganese and Nickel contents being so controlled that they satisfy the following formulae a. 4 X Al% rl-Mn% 14% 20% b. 4 X Al% +Ni% 17% 25% c. Ni%/5Al% Greater than 1 1 Claim, No Drawings COPPER NICKEL ALLOYS This Application is a Continuation-in-Part of application Ser. No. 784,024 filed Dec. 12th, 1968, now abandoned.

This invention relates to the production of high quality, high strength, castable, weldable and corrosion resistant Copper Nickel'alloys containing additions of Aluminium, Manganese, Iron and optionally Chromium.

The invention has for its object to produce alloys which satisfy the following exacting criteria 1. In the as cast condition the alloy fulfils the requirements of the weld test set outinASTM B369-61T.

2. The alloy possesses a 0.5 percent Proof Stress of at least 17.5 tons per square inch in the as cast condition, and should respond to heat treatment to give even higherstrength.

3. The alloy possesses an Ultimate Tensile Strength of at least 30 tons per square inch in the as cast condition.

4. The alloy possesses a high degree of ductility as represented by an Izod Impact value of at least 26 ft.lbs. in theas cast condition, and at least 23 ft.lbs. even after heat treatment for four hours at 550C.

5. The alloy has a low magnetic permeability not exceeding 1.05.

6. The alloy is strongly resistant to corrosion in sea water.

In modern marine engineering and shipbuilding practice, there is a growing demand for high quality castings used in the production of valves, pumps, heat exchangers and other components of sea water circulating systems.

High quality castings of this kind are often of intricate form and have considerable variation in sectional thickness. They require to be highly resistant to corrosion by sea water, of low magnetic permeability,preferably of below l.05, and to possess high yield and tensile strength combined with excellent ductility and notch impact strength as measured by Izod or Charpy Impact value. The alloy used should be readily castable into intricate form and as the finished product may involve a plurality of castings welded together, or the finished product may be required to be welded to another component, the alloy should be capable of beingvwelded with the weld being of excellent quality and so that the casting and the weld are radiographically sound.

Aluminium is a well-known strengthening agent for Copper Nickel alloys. However, cupro Nickels strengthened by Aluminium additions are subject to variable weldability. This can be alleviated by incorporating additions of Manganese. However, castings produced from such an alloy are only weldable if the Nickel, Aluminium and Manganese constituents are controlled within very close limits. This invention has for a principal object to define these limits and also to ensure that the resultant casting has the high criteria of strength and ductility as set out at the beginning of this Specification.

Iron is also a known strengthening agent. However, sufficient Iron must be added for its strengthening effect to be apparent, while too high an Iron content may impair the corrosion resistance of the alloy. A further object of this invention is to define a beneficial range for the Iron constituent of the alloy.

Wrought alloys having as constituents Copper, Nickel, Aluminium, Manganese and Iron are wellknown in the art.

For example, British Patent Specification No. 578,223 dating from 1942 discloses such an alloy having constituents as follows Nickel 9% 30% Aluminium 0.1% 2.0%

Manganese 5.0% 30% Iron Up to 5% Copper substantially the remainder Also in German Patent Specification No. 655,931 dating from 1933 an alloy is disclosed having constituents as follows Nickel 10% 40% Aluminium 0.1% 6% Manganese 0.5% 10% Iron 3.0% 20% Copper Substantially the remainder However, these prior references contain no teaching as to how the exacting criteria set out at the beginning of this Specification can be ensured.

On thecontrary we have found that these'criteria can be achieved with surety with an alloy consisting essentially of Copper, Nickel, Aluminium, Manganese, Iron and optionally Chromium, if the various constituents are controlled within very close limits.

Specifically the invention provides a Copper Nickel alloy consisting of the following elements in the following proportion by weight Nickel 9%' 18% Aluminium 1% 3.5%

Manganese 8.5% 13% Iron 2.5% 6.5%

Chromium 0% 1% Copper the balance I with the Aluminium, Manganese and Nickel contents being so controlled that they satisfy the following formulae: v

a. 4 X Al% Mn% l4% 20% b. 4 x Al% Ni%= 17% 25% c. Ni%/5Al% Greater than I The Chromium content is optional and confers beneficial results when the alloy is heat treated; specifically it provides more uniform dispersion of the precipitation hardening phase.

In the accompanying Tables, various examples. of alloys are shown, all of which are highly resistant to corrosion in seawater. In the Tables the values for the computation 4 X Al% Mn% are given under heading (a), the values for the computation 4 X Al% Ni% are given under heading (b) and the values for the computation Ni 5 X Al% are given under heading (c).

The alloys of Table I are examples according to this invention which all satisfy the criteria set out at the beginning of this Specification.

Table II gives examples of various alloys of a generally similar composition to those in Table I, and all of which satisfy the weld test. However, for various reasons the alloys of Table II fail to satisfy one or more of the criteria set out at thebeginning of this specification.

Specifically the alloys of Table II have lower strength coupled with high ductility than the alloy examples of Table I.

Table III gives some examples of alloys of a broadly similar composition. to those of Table I. However all the alloys of Table III suffered a significant loss-of ductility when subjected to heat treatment.

Table IV sets out various alloys also of broadly similar composition to those set out in Table I. However all the alloys in Table IV failed to satisfy the weld test according to ASTM 8369-611.

All the alloys of Table I achieve the requirements of the weld test set out in ASTM B369-61T.

All the alloys of Table I possess an 0.5 percent Proof Stress of at least 17.5 tons per square inch in the as cast condition, the results of thistest ranging from 17.6 tons per square inch, in examples 2, 10, 11 and 14, to 22.4 tons per square inch in example 17, with even higher strengths being achieved after heat treatment.

All the alloys of Table I achieved an Ultimate Tensile Strength in excess of 30 tons per square inch, in the as cast condition, and all achieved higher strengths after heat treatment.

All the alloys of Table I achie ed a satisfactory degree of ductility as measured by elongation and Izod Impact tests, in the as cast condition, and ductility was not significantly reduced after heat treatment for four hours at 550C, the examples all recording after such heat treatment, an lzod Impact value in excess of 23 ft.lbs.

The Nickel constituent of the alloys of Table I ranges from 10.7 percent in Example 14 to 18.0 percent in Example 17. The Aluminium content ranges from 1.1 percent in Example 16 to 2.35 percent in Example 1. The Manganese content ranges from 8.8 percent in Example l to 12 percent in Example 10. The Iron content ranges from 2.81 percent in Example 6 to 5.24 percent in Example 12. The Chromium content of the alloys of Table I ranges from nil in Example to 0.86 percent. in Example 7.

More importantly the Manganese and Aluminium constituents when computed by formula (a) 4A1 Mn range from 14.25 percent in the case of Example 17 to 19.9 percent in Example 6; the Nickel and Aluminium contents when computed by formula (b) 4A1 Ni range from 17.5 in Example 10 to 24.2 percent in Example 17; and in all the Examples in Table I, the Nickel content is more than five times greater than the Aluminium content.

The effect of Iron on the strength of alloys according to the invention is demonstrated by the following table where alloy examples are shown with Iron contents ranging from 0.42 percent to 3.77 percent.

n will be seen that where the Aluminium and were contents computed by formula(b) are in the range of about 19 21, an Iron content of at least about 3 percent is required if a 0.5 percent Proof Stress of at least 7 Certain of the alloys of the Tables were tested for magnetic permeability and the results shown on the Tables indicate that these alloys are substantially non-' magnetic. However, tests on an alloy consisting of 10.1 percent Manganese, 13 percent Nickel, 5.16 percent lron but only 0.04 percent Aluminium, the balance being Copper, indicated for this alloy a magnetic permeability of 1.4.

Moreover the alloys according to the invention, examples of which are shown in Table I, do not exhibit any significant variation in properties in the as cast condition in dependence upon the sectional size of the casting. As an example, an alloy consisting of Nickel 12.3 percent, Aluminium 2.03 percent, Manganese 10.6 percent, Iron 4.61 percent and Copper the balance, was produced in cast form as a 2 inch square cast bar, a 3 inch square cast bar and a 4 inch square cast bar, and was found to have properties as follows:

0.1% 0.5% Ultimate lzod Size Proof Proof Tensile Impact of Cast Stress Stress Strength Elong. Value Bar tons/in tons/in tons/in ft./lb. 2 inch square 16.8 20.2 30.8 26 29,30,29 3 inch square 16.0 20.3 30.0 21 34.30.28 4 inch square 17.4 20.0 29.2 28 27,28,32

The alloys of Table II while satisfactory so far as their ductility is concerned have significantly lower strength in the as cast condition as compared with the examples listed in Table I.

The best example in Table II is Example 5 which achieves a 0.5 percent Proof Stress of 16.6 tons per square inch in the as cast condition. This figure would undoubtedly be improved with small additions of Nickel and/or Aluminium to bring the value of these when computed by formula (b) 4A1 Ni up to g at least 17 as taught by this Specification.

Example 21 has a 0.5 percent Proof Stress of only 9.6 tons per square inch in the as cast condition and it is significant that this alloy is substantially identical in composition to some of the alloys specifically listed by way of example in the aforementioned prior British Patent Specification No. 578,223. The alloy, Example 21 also failed to respond to heat treatment. Example 21 of Table 11 may be compared with Example 7 of Table l and it will be noted that the Aluminium and Iron contents of Example 7 are significantly higher while the Nickel content is maintained at least five times greater than the Aluminium content. Thus if the Aluminium content of Example 21 were increased to above 2 percent and the Iron content were increased above 3 percent then this alloy would satisfy the criteria set out at the beginning of this Specification. Comparison may be made with Example 5 of Table I.

Examples 22 and 23 are also virtually identical with certain alloys specifically listed by way of example in the aforementioned British Patent Specification No. 578,223. However, these examples had 0.5 percent Proof Stress strengths of only 10.5 and 10.8 tons per square inch respectively and were in comparison with the alloy examples of Table I, relatively low strength ductile alloys.

The alloys of Table 111 may be compared with Examples 16 and 17 of Table I. It will be noted that the first five Examples of Table III have relatively high Manganese and Aluminium contents when computed by fortherehe ly achieved,

close limits. examples of ellent combihas not been pos- 20 sible to ensure in Copper Nickel alloys.

Magnetic permeability an alloy where e lower than Examples 42 and 43 also have low Manganese contents.

45 and 46 exhi it relatively high Nickel and Aluminium contents when computed by formula (b) 4Al Ni.

elatively high d the weld test.

ing criteria, set out at t i' ai di l yl bfs Weld test sile Elong. s r st n t Tlsq. in T7sq. in

V The first Example 41 of Table IV is of ctory'sufthe Manganese and Nickel contents ar d by Izod specified according to this invention.

Examples 44 level The last Example 47 in Table IV has a r Manganese content.

All the alloys in Table IV faile A careful study of the various examples will, fore, show that if the exact outset of this specification, are to be not on 'shg'htly less but satisfied with surety, then the various constituent m the as elements must be controlled as to their relative proportions by weight to one another, within very The alloys according to the invention, Mangawhich are given in Table I possess an exe nese content, taken in conjunction with the Aluminium nation of properties which hitherto it TABLE 1 0.1 0.5 percent percent Formula I proof proof Ten stress (b) (0) Condition T/sq. in

lity of the alloy.

(P cent) (a) I it will be seen that these alloys, while being otherwise generally satisfa st outside formula (a) at 20.4 peranese and Aluminium contents were tility after heat treatment in Table III has relatively high Nickel content so as to give a high value according to formula (b) 4A1 Ni at 25.5 percent and this ility even in the as cast condition. It

Table IV when compared mmmiaiflir given in the other Tables demonstrates the effect of the Fe Ni Cr (p (P cent) cent) Example 32 is ju cent. If the Mang The last alloy 36 y strong brittle alloy. With Nickel this alloy would have more ductil qflflilifl Mn Al (p (P cent) cent) mula (a) 4Al Mn and fered a significant loss in ductility as measure or Charpy test after heat treatment.

lowered slightly, the duc would be increased to a more satisfactory alloy had low duct is a relativel and Nickel contents, on the weldab Example 2 4 n 4 2 4 c v. 0 0 0 l 0 Sia 3 3 M 3 4 4 0 0 0 0 0 a efi 0 0 0 O O l l 1 l I Mnmm m m m m 0 0 0 e n l l P u v m r s m H m cm 0 0 0 0 0 M .m d d d d d e t W a n n n S n n a m6 m L n m 18 4, 3 4 M 6 3 6655 4253 M if 6, &2 6 8 5 2 5/4 O MM, uw 6655664253 a 0 4 6 4 26 0 8 2 .l. 34 IV 7 3 66656642fl3 5 t 0 3 85272885360 24 m em 6 34444434243 im m E MMMMMMMDMU h m 308. 9. .06384055656 lg 4433. 53727] .7..L7 33333 3 343333 mmm 2Z 2ZZ23Z3NNUN Mflod47 2 TRW 2 s 27606966490566570265628200655204062 tcus 65 5883 2652940650582 5798583o05oo 85039379737300 7 0004 no .nOSi 22 2 2 2 2 222 2. 2 2 2 22 2fl2 -fi wmmnw WWWWHMWNUV MUMM M H rPss 1 ll 1 w W 220 94960 0420800448667686550550523 tfs 83 I v t n I I I. 9358028664640050 4 72686 696 686 6 6 5 5 7 .nos.... 121112111 ,.lizlmlwiwlmu. uimnmmmwnnv mmmq wswnmmu nnm m PM l U n P T mm mm #c WT MT Mm Mm ma m. K 0 MT a u "c c C MC .0 c "c 0 0 0 0 0 O 0 0 0 0 0 0 n 0 0 0 L. .0 2. no .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 .5 "5 5 5 E m n 5 5 n5 5 5 5 5 5 5 5 5 5 5 5 u 5 5 5 L m 5 "5 "fi "M a. Y- 7 t t t Y- L: I o a i. i @m@w@ @m@s@m@m@@a@w@ m .n m@ .@m a@m@m m a C CBCECHCBCBCBCECNCHCBHBCSCEQMBMNCB .0 MSM fiSMS vS S S S S M4 ha m m m m m n e m a fi m m m smsmsmsmsfiimflfimfi 4 4 4 4 4 4 4 4 4 4. 4 a i i M m C A4 4 4 4A4A4A4A4A4 l 9 5 9 4 5 8 9 8 7 l 4 O 9 1 2 O 6 u J .1 .5 .3 @M M%. m un%w m l l l l l l l l l l l I l 1 l 3 2 l a L L M L 4 8 3 J 6 2 3 1 5 6 2 0 7 5 l 2 6 W m 0o 2 2 6 0 l 0 9 0 O 9 2 O l l 7 O 0 l 2 Z 4 3 m m l 7 5 4 6. O 9. Z l 2 2 l 7. 2 2 2 l 2 2 2 8 0 2 2 l i Q 2 i l 6 l 8 l 2 2 m 1 2 2 l H l 2 1 3 4 7 7 3 7 7. 5 l 6 6 2 5 773 99393 .137 .7 16 M llllll1ll. 11 l l 6 hu mln mnl l l l l H l l 2 l l 2 9 9 3 2 2 5 6 Z 1 l H 2 6 6 H. H.. M l l l .1 .3 .65N555NMMN u mmmwfimmmwwm 0 0 0 0 0 0 0 0 0 0 0 0 0 0 W We C W n 4 4 O l 8 2 6 3 6 6 O 0 6 7 5 7 0 8 l 0 0 0 3 2 Fl 7 0 0 0 l l 2 Z 0 l l 2 rt. liilimlnnlunnwanmo. mww vs vv m (c w 7 0 7 3 l l 6 8 8 6 8 4 9 0 6 0 0 0 a e 2 3 7 l l 7 l ssnwmuu44u4nu mssj Fum42 6 wm0mfi 4 Wu 0 4 4 4 4 4 4 5 8 9 1| 8 5 5 3 8 5 5 l 7 5 l 6 9 i 2 0 0 0 O 2 l 2 J 4 l 0 2 9 7 S 8 wm H ah Q M 2 w m 9 5 W 2 2 2 2 2 2 2 2 l 2 2 l l l l De 1 l l L l 1 3 7 l l 2 oo0 695 62075977590 n oa455 5 7 7 l 6 5 8 9 0 0 0 l 0 0 0 2 6 0 8 9 O 8 9 l a M m l 2 8 8 l I I] I l l l l l l v 4 9 8 8 9 9 9 Wm W l M 9 9 9 9 m k W 0 l 2 L 4 5 6 7 8 km a .ll 1|. 1 A l I] l I II I II 2 3 4 5 Z 3 4 5 6 7 8 9 Ea Z Z Z 2 2 n. "U H W. m

TABLE 111 0.1 0.5 percent percent Mag- Mn 1 A] Fe N1 Cr Formula proof proof Tensile Elong. netic Ex (perper- (per- (per- (perstress stress strength perlzod impact permeaample cent) cent) cent) cent) cent) (a) (b) (c) Condition T/sq. in T/sq. in T/sq. in cent value ft. lbs Weld test bility 1 9.7 2.81 4.16 10.7 0.53 20.9 21.9 0.76{2;$ 'by:: g'g 22% Satisfactory 2 11.75 2.16 .61 11.6 .61 20.4 20.24 1.o7{ff gg y 3;: 3 11.6 2.59 4.51 11.6 .59 21.97 21.97 0.90 {faf g' 'g y 21 2%; 4 10.5 2.63 2.28 11.8 .66 21.0 22.3 .90{; 2 3% As cast.... 16.6 20.0 33.0

12.11 2.3 4.46 12.8 .68 22.0 22.0 1.11{ A 281 4376 A5 cast 23.0 26.5 35.0 9.7 1.92 4.9 17.8 .51 17.4 25.5 1.85 b 2&2 385 I9 ZIIZLHM} ..d0 1.004

TABLE 1v 0.1 0.5 percent percent Mn Al Fe Ni Cr Formula proof proof Tensile Elong. netic 1521- (per- (per (per- (per- (perstress stress strength perlzodimpact permeaample cent) cent) cent) cent) cent) (a) (b) (c) Condition T/sq. in T/sq. in T/sq. in cent value ft. lbs Weld test bility 1 7.05 1.88 4.7 8.8 0.68 13.58 16.32 0.94{Q; ;E- :2 {g2 Q8 2 7.3 1.92 4.46 12.3 .61 14.97 19.98 1.28{Q; f%- ;.5: 52:}. 3;? 8.2 2.14 3.0 11.1 .67 16.74 19.64 1.o4{ff ggg z.g g; is"; 4 9.15 4.8 4.7 10.9 .56 28.35 30.1 114.5{22ff'55 32 Q8 5 11.2 2.47 4.37 19.9 .52 21.08 29.78 1.62{Q%'5 ;51 2f 6 13.0 3.3 4.1 13.5 .61 26.2 26.7 0.82 {Qgf gg u 55 12 352 7 17.3 2.1 4.3 11.5 .50 25.7 19.9 1.o9{fa gg y' 2'; 12 1;:

We claim 1 b- 4 .Al%il ll%.=-1 7 f .5.% l. A high quality, high strength, highly ductile, cast, c. Ni%/5Al% Greater than 1 weldable and corrosion resistant copper alloy consistsaid alloy characterized by the following properties in ing of the following elements in the following proporas cast condition: trons by weight: l. fulfills the requirements of the weld test set out in Nickel 9% 18% ASTM B369-61T Aluminium 1% 3.5% 2. possesses a 0.5 percent Proof Stress of at least 17.5 Manganese 8.5% 13% tons per square inch Iron 2.5% 6.5% 3. possesses an Ultimate Tensile Strength of at least Chromium 0% 1% 30 tons per square inch Copper the balance 4. has an lzod Impact value of at least 26 ft. lbs. with the Aluminium, Manganese and Nickel contents 5. has a low magnetic permeability not exceeding being so controlled that they satisfy the following for- -0 mulae:

8 I? l II a.4 Al%+Mn%=l4%20% 

2. possesses a 0.5 percent Proof Stress of at least 17.5 tons per square inch
 3. possesses an Ultimate Tensile Strength of at least 30 tons per square inch
 4. has an Izod Impact value of at least 26 ft. lbs.
 5. has a low magnetic permeability not exceeding 1.05. 